Body Filler for concrete voids

[/pine]

Personally I would use a "float" mix made of Portland cement and fine sand...no water, just use bonding agent (see instructions on the bonding agent for mixing a slurry)...use just enough sand to make it "floatable" with a masonry sponge...float over the areas and after it has initially cured (3-6 hours depending on the ambient temp.) go back over the areas with just a wet sponge...

 

[tcreeley]

Personally I would use a "float" mix made of Portland cement and fine sand...no water, just use bonding agent (see instructions on the bonding agent for mixing a slurry)...use just enough sand to make it "floatable" with a masonry sponge...float over the areas and after it has initially cured (3-6 hours depending on the ambient temp.) go back over the areas with just a wet sponge...

You watch somebody do this?

 

[/pine]

You watch somebody do this?

FYI...I've seen it and done it many times...ask any masonry/concrete contractor you happen to know how they address a "honeycombed" section in a formed/poured (exposed finish) project...etc.,etc...( they will also tell you that on a fresh pour bonding agent is not required)...!

 

[tcreeley]

FYI...I've seen it and done it many times...ask any masonry/concrete contractor you happen to know how they address a "honeycombed" section in a formed/poured (exposed finish) project...etc.,etc...( they will also tell you that on a fresh pour bonding agent is not required)...!

You sound like you are reading it from a set of directions. Just wondered.

 

[vtsnowedin]

On bridge work they used to do what was called a class A rubbed finish. As soon as the forms were stripped they would take a rubbing stone and some water and start rubbing the wet surface in a circular pattern. It would work up a cream from the cement on the surface and fill in all the small air bubble holes and grind down any form fins. Cheaters would use a fine grind stone on an angle grinder and add on some extra cement and water paste using the same cement as the concrete was mixed with. Looked fine but they eventually decided it wasn't worth the effort as cars passing under the bridge don't look for flaws in concrete and it didn't make the bridge last any longer. No matter what you do a painted concrete wall will look like a concrete wall which is just fine.

 

[Capricious]

Body filler is polyester resin & micro balloons/ micro spheres/ glass bubbles

IF I was going to try what you propose, I would use epoxy resin in place of the polyester, along with a sandable filler. You can mix-up your own:

Fillers

I am aware of a house with a poured concrete basement that had cracks that were successfully patched with epoxy & filler.

Epoxy generally "sticks" better than polyester.

 

[ray66v]

Body filler sticks to concrete very well. It gets all over the floor in a body shop, and often takes some of the concrete with it when it is scraped off, if it has been allowed to set too long.

However, body filler is not water proof. Anyone who has tried patching a hole in a car with it, can tell you it usually doesn't hold up well if it gets damp, in freezing conditions.

Body filler also should be sanded before painting.

So the answer is, yes it can work. No it's not the best choice.

I have used successfully used epoxy, and concrete patching cement, repairing a slab before painting.

 

[Gary Fowler]

FYI...I've seen it and done it many times...ask any masonry/concrete contractor you happen to know how they address a "honeycombed" section in a formed/poured (exposed finish) project...etc.,etc...( they will also tell you that on a fresh pour bonding agent is not required)...!

I agree that for a rubbed finish on concrete, you only need a Portland cement and sand mixture that is dampened just enough so that it holds in a ball when hand squeezed. Use a wet mortar sponge to rub the mixture into the holes. There is some trial and error on getting the right amount of water in the mix at least for a non-masonry person, but it is fairy easy and cheap to do compare to using body filler AND the finish matches the concrete color

 

[/pine]

...epoxy & filler...

FWIW...Before the health risks were realized...one of the most common materials used to thicken epoxy resin for void filling purposes (in the marine industry) was shredded, ground and powdered asbestos fibers...!
Powdered asbestos was commonly used to thicken resorcinol...

 

[Capricious]

FWIW...Before the health risks were realized...one of the most common materials used to thicken epoxy resin for void filling purposes (in the marine industry) was shredded, ground and powdered asbestos fibers...!
Powdered asbestos was commonly used to thicken resorcinol...

I have thickened epoxy with Cabosil/Aerosil (fumed silica, which is probably not good to breath) along with micro balloons, milled glass fibers, and even pink fiberglass house insulation. All in "marine"use.

Haven't tried it myself, but some are using graphite on boat bottoms.